Fetal sex and the development of future type 2 diabetes: a 5-year cohort study

Purpose: Gestational Diabetes Mellitus (GDM) increases the risk of developing Type 2 Diabetes Mellitus (T2DM) postpartum, with emerging evidence suggesting that fetal sex may influence pregnancy outcomes. Some studies suggest that individuals carrying male fetuses experience diminished insulin sensitivity and higher glucose levels during pregnancy. However, it remains unclear whether fetal sex affects the long-term risk of T2DM after pregnancy. This study aimed to investigate the impact of fetal sex on the risk of T2DM up to 5 years postpartum in individuals with GDM. Methods: This retrospective analysis included pregnant individuals diagnosed with GDM, with follow-up data from Meuhedet HMO’s computerized pregnancy registry and the Israeli National Diabetes Registry. Inclusion criteria involved singleton pregnancies with GDM diagnosed via abnormal oral glucose tolerance tests (oGTT) or glucose challenge tests (GCT). Exclusion criteria were multifetal pregnancies or prior diabetes diagnosis. Maternal characteristics, obstetrics data, and T2DM incidence were compared by fetal sex using univariate and survival analyses, adjusted for confounders. Results: A total of 1637 individuals with GDM were included, with 808 carrying male fetuses and 829 carrying female fetuses. No significant differences were found in body mass index (BMI), glucose levels, or T2DM incidence between the two groups (6.2% for male vs. 7.1% for female fetuses, p = 0.48). Multivariate analysis identified maternal age and BMI as significant factors influencing the likelihood of developing T2DM. Conclusion: The risk of developing T2DM after GDM does not vary based on fetal sex.